EP0130547A1 - Spannungsschutzeinrichtung für eine Kraftanlage mit variabler Frequenz - Google Patents

Spannungsschutzeinrichtung für eine Kraftanlage mit variabler Frequenz Download PDF

Info

Publication number
EP0130547A1
EP0130547A1 EP84107379A EP84107379A EP0130547A1 EP 0130547 A1 EP0130547 A1 EP 0130547A1 EP 84107379 A EP84107379 A EP 84107379A EP 84107379 A EP84107379 A EP 84107379A EP 0130547 A1 EP0130547 A1 EP 0130547A1
Authority
EP
European Patent Office
Prior art keywords
voltage
frequency
power system
detector
variable
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP84107379A
Other languages
English (en)
French (fr)
Other versions
EP0130547B1 (de
Inventor
Nobuharu C/O Mitsubishi Denki K.K. Takata
Makoto C/O Mitsubishi Denki K.K. Ito
Sakio C/O Mitsubishi Denki K.K. Hino
Seiji C/O Mitsubishi Denki K.K. Kaneko
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP12081083A external-priority patent/JPS6013422A/ja
Priority claimed from JP12081183A external-priority patent/JPS6013423A/ja
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to DE8484107379T priority Critical patent/DE3479850D1/de
Publication of EP0130547A1 publication Critical patent/EP0130547A1/de
Application granted granted Critical
Publication of EP0130547B1 publication Critical patent/EP0130547B1/de
Expired legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
    • H02H7/09—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against over-voltage; against reduction of voltage; against phase interruption

Definitions

  • the present invention relates to an apparatus for detecting a voltage in a variable-frequency power system.
  • Fig. 1 is a block diagram of a conventional voltage detecting apparatus, wherein there are shown an AC power supply line 1, a variable-frequency power unit 2, an output transformer 3, and an AC motor 4 which is a load in the power system.
  • the secondary voltage of the output transformer 3 is detected and inputted to a protective relay (low-voltage or overvoltage relay) serving as a voltage detector.
  • a protective relay low-voltage or overvoltage relay
  • an instrument transformer 6 for converting the secondary voltage of the output transformer 3 to a value suited for the protective relay 5.
  • the AC motor 4 receives via the output transformer 3 an electric power from the AC power supply line 1 with its frequency controlled by the variable-frequency power unit 1, so that the AC motor 4 is rotated at a speed corresponding to the system frequency f inputted thereto.
  • the output of the variable-frequency power unit 2 is so controlled that the following relationship is maintained between the system voltage E and the system frequency f.
  • the detection voltage Vm is affected as well as the system voltage E by the system frequency f, if any overvoltage (or low voltage) is generated in a low-frequency driving mode of the AC motor 4, there may occur a phenomenon that the voltage detection (or fault detection in a normal state) is rendered impossible.
  • the protective relay 5 is set at a detection sensitivity within a certain range selected on the basis of the detection voltage Vm obtained when the system frequency f is equal to the commercial frequency f and the system voltage E is equal to the normal operation voltage Vs.
  • a detection value is selected for an overvoltage of 120 to 140% and a low voltage of 80 to 70%.
  • the detection voltage Vm comes to be smaller than Vs x 40% in case the system frequency is lower than fs x 40%, so that a low-voltage detection is executed even in a normal state while any overvoltage being as high as 120 to 140% of a normal value fails to be detected.
  • the voltage detecting apparatus of this invention for a variable-frequency power system is equipped with means to detect a physical quantity proportional to the system frequency, and the detected physical quantity is applied to alter the threshold value of a protective relay.
  • the apparatus comprises a voltage detector for detecting a phase voltage of the system, a frequency detector for detecting a frequency of the system, a divider for computing the voltage-to-frequency ratio of the system from the outputs of the two detectors, and means for discriminating between the presence and absence of an abnormal voltage on the basis of such ratio.
  • a pilot generator 7 is coupled with the shaft of an AC motor 4 and produces an output es, which is proportional to the rotational speed of the motor 4 and is inputted to a protective relay 5 as a threshold set signal.
  • the protective relay 5 is so connected that the detected secondary voltage Vm of an output transformer 3 is inputted thereto, and its threshold value is increased or decreased in proportion to the voltage es which is a threshold set signal. Since other components are equal to those shown previously in Fig. 1, they are represented by the same reference numerals.
  • the threshold value of the protective relay 5 always receiving the voltage es is not kept fixed but is increased or decreased in accordance with each change in the frequency. Therefore, upon occurrence of any fault in the power system, the protective relay 5 compares the input interphase (or phase) voltage with the threshold value proportional to the system frequency f in the abnormal state of the system, In an exemplary case where the relay sensitivity is so established as to detect a 130% (or 75%) voltage when the system frequency f is equal to a commercial frequency fs, if the frequency f at the occurrence of an abnormal voltage is fs x 40%, the threshold value is lowered to 40% so that a detection signal is outputted properly even at the abnormal system voltage.
  • the above embodiment may be so modified that the output of the pilot generator 7 and the secondary voltage of the output transformer 3 fed to the protective relay 5 via the instrument transformer may be fed via input devices (not shown) respectively through signal level conversion.
  • the output es of the pilot generator 7 is not exactly proportional to the system frequency f. However, since the slip thereof is merely 5% or so, it is ignorable in practical use.
  • a detector may be provided to detect some other physical quantity such as voltage, current or rotational speed proportional to the system frequency f, and the detected physical quantity may be used as the aforesaid input signal to determine the threshold value either directly or through signal level conversion.
  • Fig. 3 An example of such modification is shown in Fig. 3.
  • an interphase (or phase) voltage in the system is introduced via an instrument transformer 6 to a voltage detector 8, whose output is then applied to a protective relay 5 either directly or through signal level conversion by an unshown input device so as to be suited to determine the threshold value of the relay 5. Since the voltage is proportional to the system frequency f, the effect attainable is equal to that in the foregoing embodiment of Fig. 2.
  • processing in the protective relay 5 may be in either an analog or digital mode.
  • Fig. 4 shows another embodiment of the present invention, wherein the same reference numerals as those used in Figs. 2 and 3 denote equal or equivalent components.
  • an interphase (or phase) voltage Vm obtained from an instrument transformer 6 is introduced to both a digital voltage detector 11 and a digital frequency detector 12.
  • a digital voltage detector 11 converts an interphase (or phase) voltage Vm into a digital value Vmd, which is then fed to the divider 13.
  • Kod constant
  • the digital frequency detector 12 has a function of converting the interphase (or phase) voltage Vm into a frequency fg at the occurrence of an abnormal voltage in the system, and the digital frequency fd is fed to the divider 13.
  • Kfd constant
  • the divider 13 computes the voltage-to-frequency ratio from the outputs of the two detectors 11 and 12 and sends out the digital value VF shown below.
  • KD Kod/(Kfd . fs)
  • the voltage discriminator 14 In response to the digital value VF thus received, the voltage discriminator 14 produces a voltage detection signal in case the input digital value VF is higher than a predetermined reference value.
  • the digital value VF is not dependent on the frequency in any abnormal voltage state, so that even when this frequency is low and the interphase (or phase) voltage Vm is small, an input signal of a level corresponding to the normal operation voltage Vs is fed to the voltage discriminator 14 to render the voltage detection always possible. Consequently, with the operation frequency range of the system, the interphase (or phase) voltage is detectable properly at a fixed sensitivity.
  • system voltage is applied as an input to the frequency detector, it is also possible to apply the system current or to employ some other means such as a pilot generator connected directly to the AC motor 4.
  • the voltage detector and the frequency detector are of digital type, it is a matter of course that such detectors may be of analog type as well.
  • system load is not limited to an AC motor alone, and similar effect is attainable practically in any power system where the voltage-to-frequency ratio can be maintained constant under control.
  • the threshold value of the protective relay is reduced with decrease of the system frequency, so that it becomes possible to ensure proper detection of any abnormal-voltage fault during a low-frequency operation mode of the power system, hence enhancing the functional reliability in protection of the system against any overvoltage (or low voltage).

Landscapes

  • Protection Of Generators And Motors (AREA)
  • Emergency Protection Circuit Devices (AREA)
  • Measurement Of Current Or Voltage (AREA)
  • Measuring Frequencies, Analyzing Spectra (AREA)
EP84107379A 1983-06-30 1984-06-27 Spannungsschutzeinrichtung für eine Kraftanlage mit variabler Frequenz Expired EP0130547B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE8484107379T DE3479850D1 (en) 1983-06-30 1984-06-27 Voltage protective apparatus for variable-frequency power system

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP12081083A JPS6013422A (ja) 1983-06-30 1983-06-30 可変周波数電力系統の電圧検出装置
JP120810/83 1983-06-30
JP12081183A JPS6013423A (ja) 1983-06-30 1983-06-30 可変周波数電力系統の電圧検出装置
JP120811/83 1983-06-30

Related Child Applications (2)

Application Number Title Priority Date Filing Date
EP87117882.8 Division-Into 1987-12-03
EP87117881.0 Division-Into 1987-12-03

Publications (2)

Publication Number Publication Date
EP0130547A1 true EP0130547A1 (de) 1985-01-09
EP0130547B1 EP0130547B1 (de) 1989-09-20

Family

ID=26458328

Family Applications (3)

Application Number Title Priority Date Filing Date
EP19870117882 Expired EP0264971B1 (de) 1983-06-30 1984-06-27 Spannungsschutzschalter für eine Kraftanlage mit variabler Frequenz
EP84107379A Expired EP0130547B1 (de) 1983-06-30 1984-06-27 Spannungsschutzeinrichtung für eine Kraftanlage mit variabler Frequenz
EP19870117881 Expired EP0271777B1 (de) 1983-06-30 1984-06-27 Spannungsschutzschalter für eine Kraftanlage mit variabler Frequenz

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP19870117882 Expired EP0264971B1 (de) 1983-06-30 1984-06-27 Spannungsschutzschalter für eine Kraftanlage mit variabler Frequenz

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP19870117881 Expired EP0271777B1 (de) 1983-06-30 1984-06-27 Spannungsschutzschalter für eine Kraftanlage mit variabler Frequenz

Country Status (4)

Country Link
EP (3) EP0264971B1 (de)
KR (1) KR850000683A (de)
CA (1) CA1249338A (de)
DE (2) DE3484352D1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113765411A (zh) * 2020-06-05 2021-12-07 产晶积体电路股份有限公司 变频电源控制器

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2032912C (en) * 1990-12-21 1994-06-28 Bryan M. Latta Nonintrusive gas-level measurement apparatus
EP1819021B1 (de) * 2006-02-14 2018-06-20 Finder S.P.A. Verfahren und Vorrichtung zur Überwachung eines mehrphasigen Netzes und zur Erkennung eines Phaseausfalles basierend auf dem Phasenwinkel zwischen verketteten Spannungen

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4118749A (en) * 1976-04-02 1978-10-03 Hitachi, Ltd. Field overvoltage protecting apparatus for synchronous machine

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3546534A (en) * 1968-01-31 1970-12-08 Gen Electric Overexcitation relay
SE416757B (sv) * 1979-04-24 1981-02-02 Asea Ab Anordning anslutning till ett vexelstromsnet for att avkenna spenning i detta och att ge ett utgangsverde som er proportionellt med forhallandet mellan netets linjespenning och frekvens
DE3237800C2 (de) * 1982-08-03 1986-09-11 Loher Gmbh, 8399 Ruhstorf Schutzeinrichtung für Asynchron-Motoren

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4118749A (en) * 1976-04-02 1978-10-03 Hitachi, Ltd. Field overvoltage protecting apparatus for synchronous machine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113765411A (zh) * 2020-06-05 2021-12-07 产晶积体电路股份有限公司 变频电源控制器

Also Published As

Publication number Publication date
EP0271777A2 (de) 1988-06-22
EP0264971B1 (de) 1991-03-27
CA1249338A (en) 1989-01-24
EP0264971A2 (de) 1988-04-27
DE3484351D1 (de) 1991-05-02
EP0271777A3 (en) 1988-07-06
EP0264971A3 (en) 1988-08-03
EP0130547B1 (de) 1989-09-20
DE3484352D1 (de) 1991-05-02
KR850000683A (ko) 1985-02-28
EP0271777B1 (de) 1991-03-27

Similar Documents

Publication Publication Date Title
EP0053103B1 (de) Schaltung zum Erfassen und Melden von Fehlern und von Betriebsunregelmässigkeiten einer Batterieladeeinrichtung
EP0098721A2 (de) Differentialschutzrelaisanordnung
US4542468A (en) Ground detection arrangement for an A.C. generator
US4377833A (en) Methods and apparatus for protecting electrical reactors
EP0122366B1 (de) Vorrichtung zur Feststellung von Erdschlüssen in Versorgungssystemen mit variabler Spannung und variabler Frequenz
EP0657991B1 (de) Signalerfassungsschaltung für digitale Regelung
CA1320561C (en) Loss-of-potential supervision for a distance relay
EP0059416B1 (de) Erdschlussfehleranzeigevorrichtung zur Verwendung bei Gleichstromkreisen
EP0123129B1 (de) Einrichtung zur Anzeige eines Erdschlusses in einem Energieversorgungssystem mit variabler Spannung und variabler Frequenz
EP0130547A1 (de) Spannungsschutzeinrichtung für eine Kraftanlage mit variabler Frequenz
US5115387A (en) Circuitry and method of protecting thyristors
US2862111A (en) Automatic paralleling system
GB2244397A (en) Residual current protective device
KR890004758Y1 (ko) 가변주파수 전력계통의 정압검출장치
JPS6013422A (ja) 可変周波数電力系統の電圧検出装置
EP0120209B1 (de) Verfahren zur Erfassung der Frequenz einer Spannungsversorgung
JPH0368352B2 (de)
KR830000034B1 (ko) 보호성 계전장치
JPH0113296B2 (de)
JPS59173775A (ja) 可変電圧可変周波数電力系統の地絡検出装置
JPH0331231B2 (de)
JPS6013423A (ja) 可変周波数電力系統の電圧検出装置
JPH0113295B2 (de)
JPH0125290B2 (de)
JPH0452049B2 (de)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): CH DE GB LI

17P Request for examination filed

Effective date: 19841128

17Q First examination report despatched

Effective date: 19861105

D17Q First examination report despatched (deleted)
GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): CH DE GB LI

REF Corresponds to:

Ref document number: 3479850

Country of ref document: DE

Date of ref document: 19891026

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19930616

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19930628

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19930630

Year of fee payment: 10

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19940627

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19940630

Ref country code: CH

Effective date: 19940630

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19940627

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19950301